Question

define allergens how it caused​

Answer 1

Answer:

An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body.

Explanation:

They are caused by many ways such as

+as dust mite excretion

+pet dander

+pollen grains

+peanuts

and etc.

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